Electric heater.



PATENTED MAY 19, 1908.

H. WAHLQUIST. ELECTRIC HEATER. APPLIUATION FILED DEO. 12,1907.

WITNESSES f 1/ v w 1% +M A TTUENEYS provided with-a homisplmrical end ll and to the passage of electric current and which is description. I

able insulating 'inaterial, for instance mica,

v shown at 15, i6, and may be of German silver.

UNITED STATES.

Pn ENT' OFFICE.

ELECTRIC Specification of Letters Patent.

HEATER.

Patented May 19, 1908.

Application filed December 12, 1907. Serial No. 406,136.

phia and State of Pennsylvania, have invcnted a. new and improved Electric Heater, ot' wlnch the following is a lull, clear, and exact My invention relates to electric heaters, and more particularly to those of a. typo s 'table for heating liquids in small receptac cs, such as tea-kettles, drinking cups and the like.

Reference is to be had to-the accompanying drawings forming a part of this specification, in which similar characters of reference indicatecorrcspomling parts in all the tignros.

Figure l is-a vortical section through a teamt provided with means for sup iorting my improved heater which is suspcm ed therein, for the nlrposc' ofheating the contained liquid; Fig. 2 is an enlarged central sectiim through the heater, showing the arrangement of the heating c ils within the outer tube, and also showing the various insulating tubes associated with thecoils l'or supporting the latter; Fig. 3 is an enlarged section upon tho line I; -----3 of Fig. 2, looking in thc direction oit-he arrow, and showing nlorerin detail the arrangement o'lthe heating coils and the concentrictubes; and Fig. 4 is a lrugmentarv central section through another form of tube used as a part of my improved hc'ator.

Aycsscl 5, such as a tea-pot, containing a liquid ti to be heated, is provided with a handle 7 and with a cover h.- 'lho cover is provided centrally with an annular-bowl t) for supporting the heater. A Lube 10 of metal is mounted within the latter is ahemispherical washer 12 of insnlating-material, preferably mica. Tubes l3, 14 are disposed concrmtrically to each other and are made. of any suitclay or porcelain. The heating windings areor any-other metal otl'cring a high resistance not easily melted.

.A metallic-tube 17 is located within the tube 14'of insulating material. All of the tubes 13, 14 and iiaife supported by a washer 18 of mica or other insulating mate.- rial;- A filling 19 of cement or plaster is glisposed above the r-asher .l8 and adheres firmly to the inner surface of the-outer tube 10. The up vcr cnd'of the tube It) carries a head 20 which may be used for supporting the tube, in the manner indicated in Fig. 1. A handle '21, of glass or porcelain, is secured to the head :20. I employ glass for this purpose because itis a poor conductor of heat.

A rubber bushing 22, having, a rounded passage 2.3 through it, is mounted upon the upper end of the glass handle .21. A cable 24, containing two insulated wires .25, 26, ex-

tends through the bushing. The two wires 25, 26 are. connected by soldered or brazed joints '27, :38 with wires 25], 30 which are. practically cont inuations of the heating coils.

.ln the form shown in Fig. 4 an outer tube 31 is provided with an annular head 32 and above this is a. thread 33 engaging a'nnitin'g thread upon the lower end of a glass tube 34 which serves as a handle. in this instance, the upper end of the glass tube is roundedat 35 for the purpose of preventing abrasionof the cable. 24.

-;\ly invention is used as follows: The operator grasps the heater by the. handle 21 or 34. as the case may be; and extends the heater downwardly into the vessel, as indicated in Fig. .1. 'lho"olectric current being turned on through the cable, elevates the temperature of the heating coils iii the manner well known' The outer tubelt) contains air and as this air becomes heated it develops pressure greater than ordinary atmospheric pressure and also serves to distribute the heat. The outer tube It) being .both airtight and watertight, of course no water can roach-tho heating coils.

"lhocushion of air intermediate the. outermost of the heating coils and the outer tube It), prevents liahility; oi overheat-inn of the tube 10. The degree of heat. attainable may, of course, be regulated by regulating the electric current, but it through accident, an

excessive current should be sent through the heating coils, there is little liability of causing any damage, for the reason that the air jacket encircling the outermost heating coil does not become instantly hot enough to do the damage in questiom By aid of the device aboye described the degree of heat generated may be regulated with great nicety. Theheat may be regulated to a great extent without afiect-in the electric current, if desired,. by simply allowing the heater todescend to a predetermined distance (asccrtai iiabie by ex erience) in the liquid to be heated. It may e further reguli-gitccl by inserting the heater deeply into the fig paid, and as soon as the latter approaches 151c boiling hint, witl'nilmwin the heater to desired (extent and i101 ing it by the cndle until all of the liquid acquires the desired temperature.

E Sometimes ccnsti'ucp the outer tube 10 Of 161', in which event, it acts as u sterilizer servcs to kill certain germs which may in the water. As fihe cutcr tube is a plain, Silfil ht c linder, it is easily kept clean.

TWi .ile show and dccm'ilic the form of tin"; dwicc miitablc for heating in @110 net limit myscif tea this use cf the invcn- Lion as it may lcc 'nplcyczii in Giiml' rcla small vessels, 1

Lions coming fairly within claims.

Having thus described my invention, 1 claim as new and desire to secure by Letters Patent: v The combination of a, vessel, and an electric heater provided with a bond for cngzigin a portion of said vesscl 80 as to support sun .heater.

' In licstiinoi'iy whereof I have signcil 'iny DiLII'lQ to this specification in the pz'vscn c of tin) sqbscribi'ng Witnesses.

HJALMAR WAH LQL'IS'I Witnesses:

ROBERT :"atr svnxsozv, (1.41mi L. vwimmi'm'r.

the scope of my 

